In 1947 J. Robert Oppenheimer organized a historic conference of physicists at Shelter Island, located off the eastern tip of Long Island, to discuss recent advances in theoretical physics and the direction of future research. Over three decades later, the physics community held another meeting, the 1983 Shelter Island Conference on Quantum Field Theory and the Fundamental Problems of Physics. This volume is the record of the 1983 conference; it also includes much valuable information on the 1947 conference, for which no formal proceedings were ever published. The latter-day conference...